Apparatus for blow molding a preform in a mold with a sterile gas

ABSTRACT

A needle is retracted into a sterilization chamber where it undergoes heating to a sterilization temperature while a sterile gas is passed through the needle. The sterilized needle is then passed to a position above a mold and the needle is then extended to pierce a preform in the mold and blow the preform in the mold.

Siard et al.

451 Jan. 23, 1973 APPARATUS FOR BLOW MOLDING A PREFORM IN A MOLD WITH ASTERILE GAS Inventors: Michael Siard, 2, Route du Cap, 76 SainteAdresse; Daniel Pellerin, 11, rue J; Siegfried, 76 Le l-lavre, both ofFrance Filed: March 26, 1971 Appl. No.: 128,469

Kiifilicaihfl Priority Data MQTTfTlWTTYihEEILLL ..'LI.'.. "17611153""aster; 'LLIII.1:1...1:.lZiB/ififlfi 1791 23/290, 134/166 R, 141/90,264/94, 425/326 Int. Cl. ..B29d 23/03 Field of Search ..425/326, 387,472; 23/290;

[56] References Cited 7 UNITED STATE-S PATENTS 2,629,148 2/1953 Kollsman..21/96 X 3,351,980 11/1967 3,359,062 12/1967 3,479,793 11/19693,577,279 5/1971 Lightner et a1 ..134/23 Primary Examiner-J. SpencerOverholser Assistant Examiner-Brian P. Ross Attorney-Waters, Roditi,Schwartz & Nissen [57] ABSTRACT A needle is retracted into asterilization chamber where it undergoes heating to a sterilizationtemperature while a sterile gas is passed through the needle. Thesterilized needle is then passed to a position above a mold and theneedle is then extended to pierce a preform in the mold and blow thepreform in the mold.

4 Claims, 2 Drawing Figures PATENTEDJMI 23 Ian 3.712 784 SHEETEQFZAPPARATUS FOR BLOW MOLDING A PREFORM IN A MOLD WITH A STERILE GAS BRIEFSUMMARY OF THE INVENTION tles by extrusion from a preform and subsequentblowl0 .ing of the preform in a mold is applicable to various branchesof industry and especially the food and pharmaceutical industries. Themanufacturing process employed comprises extruding through a circulardie a tubular preform closed at its free end in order to avoidcontamination from the atmosphere, the material thereof being raised toa sufficiently high temperature and for a period long enough to ensurethorough destruction of any bacteria and microorganisms that may bepresent therein. After having been closed at its other end in asepticconditions, such preform is next transferred to a chilled mold in whichit is blown i.e. injected with a sterile gas and cooled.

To preserve the sterility of the preform, the blowing thereof in themold must be effected with a sterile fluid introduced by means of alikewise sterile needle.

An object of the invention is to provide apparatus by which the needleused in the manufacture of a hollow body by extrusion and blowing issubjected to sterilization before each injection of the hollow body witha gas.

Another object of the invention is to provide apparatus allowingrepeated sterilization of the blowing needle.

The needle-sterilization operation must be repeated after every blowingoperation, since parts connected to the needle are" exposed to theatmosphere during the blowing. Also, after blowing and cooling of thepreform, the needle also comes into contact with the atmosphere whenwithdrawn from the mold.

Another object of the present invention is to provide apparatus by whichrepeated sterilization of a hollow needle after each blowing operationof a hollow body in a mold by means of injection of a sterile gasthrough said needle. The needle can occupy a sterilization positionremote from the mold and a blowing position inside the mold and ismovable from one position to the other under the control of appropriatemeans. According to the invention the needle as well as the supportingmeans therefore, when in the sterilization position, are raised to asufficiently high temperature for a sufficiently long time forsterilization, while the inside of the needle is traversed by a gentlestream of sterile gas. During the period of travel of the sterile needlefrom the sterilization position to the blowing position, a gentle streamof sterile gas is maintained inside the needle.

When in the sterilization position, the hollow needle is retracted intoa sterilization chamber and the needle and support means therefor areheated to temperature high enough to effect thorough sterilization. Theinside bore of the needle is connected with a sterile gas source and istraversed by a stream of the gas. This may be sterile air. A lowfeed issatisfactory in this stage of the process. Advantageously, during theinitial sterilization of the needle, a current of steam is passedtherethrough so as to sterilize the entire blowing circuit.

When the necessary time for sterilization has passed, the feed ofsterile air to the needle is increased so as to cool the walls thereof;this precaution prevents adherence of material to the needle when thelatter pierces the preform to be blown.

To effect blowing, the sterile needle is introduced into a passage inthe mold. During the travel of the needle from the sterilizationposition to the blowing position, it is advantageous to maintain a lowfeed of sterile air inside the sterile needle, so as not to produceturbulence which might cause contamination of the preform or of the moldby impurities from the atmosphere.

It is necessary that the passage in the mold in which the needle isintroduced should also be sterile; this can be attained by blowing asterilizing gas within said passage. The needle is supported in a collarprovided with a shoulder which in the blowing position, provides a sealfor the passage in the mold.

Blowing is effected with a sterile gas, such as air at a much higherpressure compared to that during the travel of the needle from thesterilization position to the blowing position.

After blowing, the needle is returned to its-sterilization positioninside the chamber to be made ready for a new cycle of operation.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic elevation view ofthe device in sterilization position; and

FIG. 2 shows the same device in a blowing or injecting position.

DETAILED DESCRIPTION thereof between the retracted state in thesterilization position in FIG. 1 and the extended state in the injectingposition in FIG. 2. I

Chamber 2 has walls which are thermally insulated from the ambientatmosphere. Mounted at the inside wall of the chamber is an electricalheating resistance 4, whose temperature can be raised high enough toattain sterilization of the needle in a given time. The resistance 4 canbe connected via a thermostat to a power supply (not shown).

The needle is engaged in a supporting collar 5 which can be be axiallydisplaced by a jack (not shown) to move needle between the retracted andextended states. Connected to the collar 5 is a bellows 6 which servesas a seal between the collar and the interior of chamber 2. The bellows6 can be constructed of stainless steel or laminated bronze with athickness between 0.1 and 0.2 mm; or polytetrafluorethylene or siliconerubber.

The bore of the needle can be selectively placed into communication witha sterile air circuit 7 and a steam system 8. A trough 9 is disposedbeneath chamber 2 to collect condensate when a first sterilizationoperation is effected with steam. A jack 10 is connected to chamber 2 todisplace the chamber from the sterilization position above trough 9 tothe injecting position above an inlet passage 11 ofa mold 12.

In operation, the needle 1 is retracted into chamber 2 and is initiallyconnected to the steam system 8 in the position shown in FIG. 1 so as tosterilize the entire blowing circuit. The system 8 is then disconnectedfrom the needle and air circuit 7 is connected thereto to effect agentle flow of sterile air through the needle as it is being heated tosterilization temperature within the chamber 2. After the needle hasbecome sterilized, the flow of sterile gas through circuit 7 isincreased to cool the needle and present adherence of the needle when itsubsequently pierces the preform. The jack 10 is then activated to movethe chamber 2 above mold 12. In the course of the movement of thechamber 2, a low feed of sterile air is maintained inside the needle.The needle is then extended and passes through passage 11 in mold l2 andpierces a preform in the mold while collar 5 seals passage 11. The feedin circuit 7 is then greatly increased and the needle injects sterileair into the preforming to expand the same against the walls of the moldand complete the blowing operation.

The invention can be implemented whatever the direction of the variouselements forming the device and in particular whatever the direction ofthe needle. Moreover the invention is not limited to the case where themold is stationary and the chamber mobile.

Machines for making the hollow bodies can have extremely high rates ofoperation, and hence the stay of the needle in the sterilization chambermay be too short to attain thorough sterilization. Therefore a pluralityof sterilization chambers may be associated with a single mold, thedifferent needles operating in such case in succession with the mold, asfor example by successive rotation of the chambers in front of the mold.When one needle is in injecting position, the other needles areretracted and undergoing sterilization.

What is claimed is:

1. Apparatus for blow molding a preform in a mold with a sterile gas,said apparatus comprising a sterilization chamber, a hollow needlesupported in said chamber for movement between a retracted position andan extended position, means for heating said chamber to a sterilizationtemperature, means for displacing said chamber between a sterilizationposition in which the needle is retracted and the chamber is heated tosterilization temperature and a second injecting position adjacent themold whereat the needle can be extended to pierce a preform in the mold,and means for passing sterile gas through the needle.

2. Apparatus as claimed in claim 1 comprising means for passing steamthrough said needle in the sterilization position before the sterile gasis passed through the needle.

3. Apparatus as claimed in claim 2 comprising a trough positionedbeneath said chamber in said sterilization position to receive steamcondensate passed through said needle.

4. Apparatus as claimed in claim 1 wherein said chamber is provided withan aperture coaxial with said needle to permit passage thereof betweenthe retracted and extended positions, said means for heating the chambercomprising electrical heating resistances in said chamber around saidneedles; and a bellows connecting said needle and chamber and servingtoconvey sterile gas to the needle in isolation from the interior of saidchamber.

1. Apparatus for blow molding a preform in a mold with a sterile gas,said apparatus comprising a sterilization chamber, a hollow needlesupported in said chamber for movement between a retracted position andan extended position, means for heating said chamber to a sterilizationtemperature, means for displacing said chamber between a sterilizationposition in which the needle is retracted and the chamber is heated tosterilization temperature and a second injecting position adjacent themold whereat the needle can be extended to pierce a preform in the mold,and means for passing sterile gas through the needle.
 2. Apparatus asclaimed in claim 1 comprising means for passing steam through saidneedle in the sterilization position before the sterile gas is passedthrough the needle.
 3. Apparatus as claimed in claim 2 comprising atrough positioned beneath said chamber in said sterilization position toreceive steam condensate passed through said needle.
 4. Apparatus asclaimed in claim 1 wherein said chamber is provided with an aperturecoaxial with said needle to permit passage thereof between the retractedand extended positions, said means for heating the chamber comprisingelectrical heating resistances in said chamber around said needles; anda bellows connecting said needle and chamber and serving to conveysterile gas to the needle in isolation from the interior of saidchamber.